[rdtsc]

> Whilst falling you feel weightless - almost by definition (if you and the weighing machine are accelerating in sync, you apply no pressure to it).

Ah but how often do have a chance to feel weightless? Unless you are on a space station, bungee or parachute jumping? So the feeling of weightlessness itself is pretty startling.

Also it is the moment from when you are standing on something and get pushed over the edge and then all of the sudden you are falling that is quite startling.

Think back on a dream of you falling. Everyone has those. For me, it is always the weightlessness that is shake me up and wakes me.

[ars]

Feeling weightless feels EXACTLY like falling. It does not feel like floating.

[joeguilmette]

I disagree. I have around a thousand skydives. The only time I feel a sense of falling is when acceleration is involved. When acceleration is involved, weightlessness is not.

When jumping out of an aircraft you are already going around 100mph, close to terminal velocity. There is not a pronounced sensation of falling. It feels more like laying on your stomach in water, it a bit windier.

When jumping out of a stationary object, the feeling of falling is quite pronounced until you stop accelerating. A hot air balloon or helicopter produces this effect (and is pretty damn fun). While I've never done it, BASE jumping provides a similar sensation.

[ars]

Why do you disagree? You are describing EXACTLY what I said.

Did you typo and mean to write agree?

When you hit terminal velocity you are no longer in free fall, I would expect it to feel like pressing lightly on something - which is what you describe.

To be in free fall you have to be accelerating (that's why it's called free fall and not zero gravity), and again that's what you describe.

This is not a correct sentence: "When acceleration is involved, weightlessness is not." In fact it's exactly the oppose of that.

You can't have zero gravity near the earth - the earth has gravity, and you can't get away from it. Instead you accelerate at exactly the same speed as the acceleration from gravity. In order not to hit the ground due to your acceleration you move in a big circle and keep missing the ground.

The reason you don't keep getting faster and faster is that you keep accelerating in a different direction, your average is zero, but you are always accelerating, just in different directions (and you make sure to always put the earth in the right place to match your acceleration).

People on the space station feel like they are falling the entire time. Presumably they get used to it after a while, but that's what it feels like.

[joeguilmette]

You said feeling weightless feels like falling.

I don't know where you get the idea that being weightless feels like falling. Astronauts always feel like they're falling? Do you have a source for that?

They dive bomb a 747 to simulate zero g to train astronauts. I've done it is smaller planes. It feels like your are weightless - floating a pool. It does not feel like you're falling, like you just fell off a roof or a hot air balloon. When you fall, your stomach drops. You go from 0mph to fast.

When skydiving you do not feel like you're falling. Sometimes you get little stomach drop when you leave the plane (the 30mph increase in speed) but after you hit terminal you feel weightless and the sensation of falling is gone - you are no longer accelerating.

Now, we call this state freefall and you say freefall is the state prior to this, when you are accelerating towards terminal. I don't know the physics behind it, nor do I have a grasp on the nomenclature as you do.

That said, I have felt it with my body many thousands of times.

When you jump off something that isn't moving you feel like you're falling because you're accelerating (like a rollercoaster). When you hit terminal you no longer feel like you're falling, you feel weightless, an entirely different sensation, similar to laying in a pool. You have no sense that you are moving at all, let alone at 120mph.

I have never been in space, but I've been in zero g bouncing around the inside of a plane and I can tell you it in no way feels like falling. At all. Not even a little. No way astronauts feel like they're falling the whole time they're in space. They probably feel - weightless :)